fix(HEL-482): 开盘前分时回退最近交易日，并接通中枢失败回旧通道

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

backend/data/gateway.py

@@ -85,12 +85,13 @@ def build_data_gateway(
     policy = DataSourcePolicy.load()
     settings = datahub_settings or DatahubSettings.load(credentials=credentials)
     datahub_client = DatahubClient(settings)
+    datahub = DatahubBridge(settings, datahub_client)
     return DataGateway(
         policy=policy,
         quality=DataQualityGate.load(policy),
         tushare_provider=TushareProvider(token_supplier),
         ifind_provider=IfindProvider(ifind),
-        chart_data=MarketChartClient(ifind, EastmoneyChartClient()),
+        chart_data=MarketChartClient(ifind, EastmoneyChartClient(), datahub),
         realtime_observer=WebRealtimeAggregator(),
-        datahub=DatahubBridge(settings, datahub_client),
+        datahub=datahub,
     )